Contents

Chapter Description

This chapter focuses on the core network layer functions of addressing and routing as covered on the CCNA/CCENT ICND1 100-101 exam. The first section of this chapter looks at the big concepts, while the second section looks at the specifics of how to write and type IPv6 addresses.

Troubleshoot and correct common problems associated with IP addressing and host configurations.

IPv4 has been a solid and highly useful part of the growth of TCP/IP and the Internet. For most of the long history of the Internet, and for most corporate networks that use TCP/IP, IPv4 is the core protocol that defines addressing and routing. However, even though IPv4 has many great qualities, it does have some shortcomings, creating the need for a replacement protocol: IP version 6 (IPv6).

IPv6 defines the same general functions as IPv4, but with different methods of implementing those functions. For example, both IPv4 and IPv6 define addressing, the concepts of subnetting larger groups of addresses into smaller groups, headers used to create an IPv4 or IPv6 packet, and the rules for routing those packets. At the same time, IPv6 handles the details differently, for example, using a 128-bit IPv6 address rather than the 32-bit IPv4 address.

This chapter focuses on the core network layer functions of addressing and routing. The first section of this chapter looks at the big concepts, while the second section looks at the specifics of how to write and type IPv6 addresses.

“Do I Know This Already?” Quiz

Use the “Do I Know This Already?” quiz to help decide whether you might want to skim this chapter, or a major section, moving more quickly to the “Exam Preparation Tasks” section near the end of the chapter. You can find the answers at the bottom of the page following the quiz. For thorough explanations, see DVD Appendix C, “Answers to the ‘Do I Know This Already?’ Quizzes.”

1. Which of the following was a short-term solution to the IPv4 address exhaustion problem?

IP version 6

IP version 5

NAT/PAT

ARP

2. A router receives an Ethernet frame that holds an IPv6 packet. The router then makes a decision to route the packet out a serial link. Which of the following statements is true about how a router forwards an IPv6 packet?

The router discards the Ethernet data link header and trailer of the received frame.

The router makes the forwarding decision based on the packet’s source IPv6 address.

The router keeps the Ethernet header, encapsulating the entire frame inside a new IPv6 packet before sending it over the serial link.

The router uses the IPv4 routing table when choosing where to forward the packet.

3. Which of the following is the shortest valid abbreviation for FE80:0000:0000:0100:0000:0000:0000:0123?

FE80::100::123

FE8::1::123

FE80::100:0:0:0:123:4567

FE80:0:0:100::123

4. Which of the following is the shortest valid abbreviation for 2000:0300:0040:0005:6000:0700:0080:0009?

2:3:4:5:6:7:8:9

2000:300:40:5:6000:700:80:9

2000:300:4:5:6000:700:8:9

2000:3:4:5:6:7:8:9

5. Which of the following is the unabbreviated version of IPv6 address 2001:DB8::200:28?

2001:0DB8:0000:0000:0000:0000:0200:0028

2001:0DB8::0200:0028

2001:0DB8:0:0:0:0:0200:0028

2001:0DB8:0000:0000:0000:0000:200:0028

6. Which of the following is the prefix for address 2000:0000:0000:0005:6000:0700:0080:0009, assuming a mask of /64?